Podcast
Questions and Answers
What is the primary focus of process geomorphology?
What is the primary focus of process geomorphology?
What is the oldest year-by-year record of geomorphic processes?
What is the oldest year-by-year record of geomorphic processes?
When did geomorphologists begin to direct process studies towards the construction of models for predicting short-term changes in landforms?
When did geomorphologists begin to direct process studies towards the construction of models for predicting short-term changes in landforms?
What is the primary goal of modeling geomorphic processes?
What is the primary goal of modeling geomorphic processes?
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What is the significance of the flood levels of the River Nile in Lower Egypt?
What is the significance of the flood levels of the River Nile in Lower Egypt?
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What is the focus of process studies and global environmental change?
What is the focus of process studies and global environmental change?
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When were the first efforts made to measure weathering rates?
When were the first efforts made to measure weathering rates?
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What is the significance of the transport of debris by running water?
What is the significance of the transport of debris by running water?
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What is the focus of geomorphologists in the modern era?
What is the focus of geomorphologists in the modern era?
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What is the significance of the rates of modern denudation in some of the world’s major rivers?
What is the significance of the rates of modern denudation in some of the world’s major rivers?
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Study Notes
Stratigraphical Relationships and Chronologies
- Observed stratigraphical relationships provide relative chronologies, which are events placed in order of occurrence without accurately fixed dates.
- Absolute chronologies are derived from sequences dated using historical records, radiocarbon analysis, dendrochronology, luminescence, paleomagnetism, and more.
Quaternary Geomorphology
- Environmental changes over the last couple of million years have led to significant adjustments in many landforms and landscapes.
- Climatic swings from glacial to interglacial conditions have altered geomorphic process rates and regimes in landscapes, causing disequilibrium and increases in geomorphic activity.
- These changes resulted in the reshaping of hill slopes, reworking of regoliths, and changes in sediment stores in valley bottoms.
Long-term Geomorphology
- Studies of landforms and landscapes older than the Quaternary or late Quaternary period are called long-term geomorphology.
- Long-term geomorphology depends on landform analysis and relative dating, as most absolute dating methods fail for the timescales of interest.
- Accurately dating long-term development landforms is challenging, and later processes often alter or destroy them.
Historical Geomorphology
- All landforms have a history, but some, like ripples on beaches, are short-lived and often unrecorded.
- More persistent landforms at various scales, such as coastal features, landslides, and river terraces, provide clues to past processes and events.
- Historical geomorphology focuses on understanding landscape history by mapping morphological and sedimentary features.
Foundations of Historical Geomorphology
- Historical geomorphologists traditionally worked to understand landscape history by mapping features and using the dictum that "the present is the key to the past".
- This approach assumes that the effects of geomorphic processes seen today can be used to infer causes of landscape changes in the past.
Process Geomorphology
- Process geomorphology is the study of the processes responsible for landform development.
- It involves measuring and modeling geomorphic processes, such as fluvial processes, to understand landform development.
Measuring Geomorphic Processes
- Some geomorphic processes have a long record of measurement, such as flood levels of the River Nile and sediment carried by the Mississippi River.
- Measurements of weathering rates, dissolved load of rivers, and chemical denudation rates have been made over the years.
Modeling Geomorphic Processes
- Since the 1960s and 1970s, geomorphologists have directed process studies towards constructing models for predicting short-term changes in landforms.
- These models draw on soil engineering, hydraulic engineering, and other fields to understand and predict geomorphic processes.
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Description
Understanding stratigraphical relationships and chronologies in geomorphology, including Quaternary and long-term geomorphology. Learn about relative and absolute chronologies, and their applications.
